Device for detecting air flow

Abstract

A device for detecting a flow of a first gas in a conduit includes a gas jet interfaced to a side of the conduit. The gas jet emits a jet of gas aimed across the conduit. A fluid port is interfaced to a distal side of the conduit for receiving the jet of gas and a pressure-detecting device is interfaced to the fluid port. In absence of the flow of the first gas within the conduit, the gas jet enters the fluid port and the pressure-detecting device reports a first pressure. In presence of the flow of the gas within the conduit, the gas jet is deflected away from the main port by the flow of the first gas and the pressure-detecting device reports a second pressure, the second pressure being lower than the first pressure.

What is claimed is: 
     
       1. A device for detecting flow of a first gas in a conduit, the device comprising:
 a gas jet interfaced to a side of the conduit, the gas jet emitting a jet of a second gas aimed across the conduit; 
 a fluid port interfaced to a distal side of the conduit for receiving the jet of the second gas; 
 means for detecting pressure of the jet of the second gas fluidly interfaced to the fluid port; 
 whereas a first rate of flow of the first gas within the conduit deflects the jet of the second gas towards the fluid port and a first pressure is present at the means for detecting pressure; and 
 whereas a second, different rate of flow of the first gas within the conduit deflects the jet of the second gas away from the fluid port and a second pressure is present at the means for detecting the pressure; and 
 whereas the second pressure is lower than the first pressure. 
 
     
     
       2. The device for detecting flow of the first gas in the conduit of  claim 1 , wherein the first gas and the second gas are the same. 
     
     
       3. The device for detecting flow of the first gas in the conduit of  claim 1 , further comprising a second means for detecting pressure of the jet of the second gas, the second means for detecting pressure fluidly interfaced to the a second fluid port interfaced to the distal side of the conduit for receiving the jet of the second gas during the second, different rate of flow of the first gas within the conduit. 
     
     
       4. The device for detecting flow of the first gas in the conduit of  claim 1 , wherein the means for detecting pressure is a diaphragm, the fluid port fluidly interfaced to a first side of the diaphragm. 
     
     
       5. The device for detecting flow of the first gas in the conduit of  claim 4 , further comprising a second fluid port interfaced to the distal side of the conduit for receiving the jet of the second gas during the second, different rate of flow of the first gas within the conduit, the second fluid port fluidly coupled to a second, opposing side of the diaphragm. 
     
     
       6. The device for detecting flow of the first gas in the conduit of  claim 1 , wherein the means for detecting pressure at the fluid port is a pressure sensor. 
     
     
       7. The device for detecting flow of the first gas in the conduit of  claim 1 , wherein the fluid port is a graduated port having a smaller cross-sectional area at one end of the graduated port and a greater cross-sectional area at a distal end of the graduated port. 
     
     
       8. A device for detecting a flow of a first gas in a conduit, the device comprising:
 a gas jet interfaced to a side of the conduit, the gas jet emitting a jet of a second gas aimed across the conduit; 
 a fluid port interfaced to a distal side of the conduit for receiving the jet of the second gas; 
 a diaphragm interfaced to the fluid port; and 
 whereas upon a first flow rate of the first gas within the conduit, the gas jet enters the fluid port and exerts a pressure on a first side of the diaphragm and moves the diaphragm in a first direction; 
 whereas upon a second flow rate of the first gas within the conduit, the gas jet is deflected away from the fluid port and the pressure decreases on the first side of the diaphragm and moves the diaphragm in a second direction opposite of the first direction. 
 
     
     
       9. The device for detecting the flow of the first gas in the conduit of  claim 8 , wherein the first gas is the same as the second gas. 
     
     
       10. The device for detecting the flow of the first gas in the conduit of  claim 8 , further comprising a second fluid port interfaced to the distal side of the conduit for receiving the jet of the second gas. 
     
     
       11. The device for detecting the flow of the first gas in the conduit of  claim 10 , whereas upon the second flow rate of the first gas within the conduit, the gas jet enters the second fluid port and pressure increases on a second side of the diaphragm and moves the diaphragm in the second direction; and
 whereas upon the first flow rate of the first gas within the conduit, the gas jet is deflected away from the second fluid port and the pressure decreases on the first side of the diaphragm and moves the diaphragm in the first direction. 
 
     
     
       12. The device for detecting the flow of the first gas in the conduit of  claim 8 , wherein the fluid port is a graduated port having a smaller cross-sectional area at one end of the graduated port and a greater cross-sectional area at a distal end of the graduated port. 
     
     
       13. A device for detecting a flow of a first gas in a conduit, the device comprising:
 a gas jet interfaced to a side of the conduit, the gas jet emitting a jet of a second gas aimed across the conduit; 
 a first fluid port interfaced to a distal side of the conduit for receiving the jet of the second gas, the first fluid port for receiving the jet of the second gas in absence of the flow of the first gas; 
 a second fluid port interfaced to the distal side of the conduit for receiving the jet of the second gas, the second fluid port for receiving the jet of the second gas when the jet of the second gas is deflected by the flow of the first gas in a first direction; 
 a diaphragm, a first side of the diaphragm fluidly interfaced to the fluid port and a second, opposing side of the diaphragm fluidly interfaced to the second fluid port; 
 whereas in absence of the flow of the first gas, the diaphragm is moved in a first diaphragm direction by a pressure of the jet of the second gas entering the fluid port and in presence of the flow of the first gas, the diaphragm is moved in a second diaphragm direction by the pressure of the jet of the second gas entering the second fluid port, the second diaphragm direction being opposite the first diaphragm direction. 
 
     
     
       14. The device for detecting the flow of the first gas in the conduit of  claim 13 , wherein the first gas is the same as the second gas. 
     
     
       15. The device for detecting the flow of the first gas in the conduit of  claim 13 , wherein the fluid port and the second fluid port are graduated ports having a smaller cross-sectional area at one end of each of the graduated ports and a greater cross-sectional area at a distal end of each of the graduated port.